Prior devices for dispensing particulate materials have included such devices as canisters with apertures in the top surface, containers with rotating applicators disposed in a top opening and applicators that are dipped in the particulate substance and then applied to the surface. For example, U.S. Pat. No. 853,405 to Godward discloses a dispenser for applying tooth powder onto a toothbrush. The dispenser is a device that is used with a conventional powder container. The applicator comprises a rolling cage having a perforated periphery that is located between the endwalls of the container. In operation, when the container is inverted powder will fall through the perforations in the cage. The cage is placed against an object, such as a toothbrush, and rotated, thereby dispensing the powder through the perforations and onto the toothbrush. This invention may work well for tooth powder, but larger grain particulates present delivery difficulties. Also, this device requires attachment to a canister already containing powder and inversion of the device for it to work.
Other dispensers comprising rolling applicators are known in the art. However, many of these are for applying liquid substances. U.S. Pat. Nos. 4,555,196 to De Garmo and 4,128,350 to Gamache are examples of liquid applicators. These devices also must be attached to a container already holding a substance. Furthermore, these devices would become clogged if they were used with relatively large size particulate materials.
Another disadvantage of prior art dispensers is that they have to be used in an inverted position because gravity is used to hold the material to be dispensed against the applicator.
A need exists for a roll-on applicator for dispensing particulate materials which is self-contained, provides a wide coverage area per stroke, can accommodate different-sized particulates, can be used in a non-inverted position and overcomes the other disadvantages associated with the prior art.